1: watch jairus of all construction videos

2: understand how it all works

3: draw the different aluminum party

4: cut out the ones you drew
and try to make the system in (EVA) mousse for example

5: if your system works well
you can pass a draw the true measure

6 : then cut out your pieces in an aluminum plate 1 mm / 1.5 mm thick

then assemble the different piece cutting in the aluminum with the help of the video of jairus of all (Iron Man Rocket Launcher Build Part 5)